Transfer roll



Feb. 2, 1965 F. w. BRODERICK TRANSFER ROLL Filed Dec. 21, 1962 UnitedStates Patent 3,167,850 TRANSFER ROLL Frank W. Broderick, P.0. Box 2,Stirling, NJ. Filed'Dec. 21, 1962, Ser. No. 246,627 3 Claims. (Cl.29-121) This invention relates to an engraved metal roll havingpatterned cavities therein adapted to uniformly transfer metered amountsof solution to a non-Woven fabric in tangential contact therewith.

In the manufacture of non-woven fabric from long fila- The engraveddesign disposed on the application roll is A of such depth andconfiguration asto transfer the solution to the non-woven fabric, inextremely closely held tolerances, said solution being then spread bycapillary action in given areas to yield a moistened binding channelhaving a uniform amount of solution per square inch.

The production of non-woven fabric is big business, as the material isused for disposable diapers, sanitary napkins, suit paddings, wipercloths, napkins, etc.

The present method of making engraved transfer rolls is by meansof aconventional mill and die wherein a small female roll is first preparedand from this a coacting small male roll is made. This male roll of afew inches in length is then repeatedly linearly transferred to thesurface of a large, sometimes six to ten feet long, production roll.Clearly, this procedure is very expensive since it requires highlyskilled labor and is very cumbersome and time consuming.

Attempts have been made to produce a suitable acid etched engravedtransfer roll using conventional acid resist coatings but the resultingembossed cavities of the pattern were provided with undesirable sawtooth or ragged edges which engaged or picked up the tiny fila ments ofthe fabric, a highly undesirable result.

Accordingly, it is impossible to produce satisfactory acid etchedembossed steel transfer rolls of the type desired above before thisinvention was made.

In the conventional method of etching steel rolls, as described forexample in Broderick US. 2,887,042, a relatively soft steel roll isphoto-engraved and then acid etched to the desired depth and finallyheat hardened to withstand usage.

This invention reverses the prior art and in so doing produces a newprocess with unobvious desirable results.

According to this invention the soft steel roll is suitably heathardened before it is photo-engraved. This heat hardening, it was found,refined the steel grain structure so that the roll could be now acidetched to produce smooth cavities having straight and uniform edges inlieu of the prior art saw tooth edges and irregular depths.

It is an object of this invention to produce acid etched engraved metaltransfer rolls for the transfer of uniform amounts of solution tonon-woven fabric, the cavities thereof having smooth, straight or snagproof edges.

It is another object to provide an inexpensive snag proof transfer roll.

It is a further object to provide an engraved pattern having greataccuracy and uniform depth of cavities.

These and other objectives of this invention will become apparent uponreading the following descriptive disclosure taken in conjunction withthe accompanying drawing in which:

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FIG. 1 is a diagrammatic perspective view of a schematic engraved rolldisposed in part in a fountain containing the binder or adhesivesolution and showing the use of a doctor blade to scrape off excesssolution from the surface,

FIG. 2 is a cross-section view of a heat hardened acid etched metal rollshowing the smooth, accurate edges and smooth, rounded internal contourof a single linear cavity as produced by this invention,

FIG. 3 is a section view of the roll of FIG. 2 after being chromeplated, showing the manner of chrome plating building up on the roundedges. of the cavities, and

FIG.'4 is the cross-section view of the roll of FIG. 3 after thebuilt-up or hump-like rounded edges have been polished off to produce achrome plated transfer roll of uniform radius.

In the use of this invention there is employed a binder or adhesivesolution used to bind or adhere the non- Woven fibers together. Thissolution is disposed in a trough or fountain and the embossed transferroll is partly placed therein. A doctor blade engages the smooth surfaceof the transfer roll and removes the excess solution thereon. The amountof solution transferred to the web is critical since too little solutionwill not effect a binding together of the fibrous filaments and too muchcured removeably thereto. An embossed transfer roll 12,

for example of herringbone pattern, is disposed partly in the fountain10. A continuously moving web 13 of nonwoven fibers is passedtangentially over the top of the embossed transfer roll 12 and engageson its opposed side a backup roll 14. The, binder solution strikesthrough the non-woven fabric to the opposite side thereof binding thelong fibers in the manner similar to that of a stitched line. In short,the binder solution from the rotating cavities is transferred to themoving web and in effect stitches the long fibers laterally to form asemi-quilted soft nonwoven fabric.

To effect this critical uniformity of binder, the engraved rolls musthave a precisely predetermined pat-tern and this pattern must accuratelytransfer a critical amount of solution per lateral area orcircumferential surface.

According to this invention, a polished suitable high carbon steel orsteel alloy roll is heat hardened, preferably by flame hardening to adesired fine grain structure. Preferably this desired fine grainstructure is produced throughout the steel roll. However, a fine grainstructure in the surface of suitable depth on the radius is operable.

This fine grain structure is homogeneous throughout the pattern area anddepth and is essential and critical to the success of this invention.

By way of an illustrative embodiment of this invention a smooth surfacedforged chrome-molybdenum steel roll, AISI 4150, having the followingcomposition:

Carbon range 0.45-0.55% by weight Manganese range 0.60-0.90% by weightPhosphorous (maximum) 0.040% by weight Sulfur (maximum) 0.050% by weightChromium range, about 0.80 to about 1.10% by weight Molybdenum range,about 0.15 to about 0.25% by weight was flame hardened to a criticaltransformation temperature of 1575 F. to produce the desired homogeneousfine grain structure as shown by microscopic examination and by aRockwell hardness tester C scale reading of 53. At this temperature thefinest grain structure was obtained which structure gave the smoothestcavities on acid etchmg.

Other chrome-molybdenum alloy steels in the range of the AISI 4150composition are operable. In general, the

alloy steel is heatedto within ten degrees Fahrenheit of their finaltransformation point in order toobtain the desired fine grain structure.Such heat treated steels exhibit a Rockwell C scale hardness readinggenerally from 45-60 and:are operable in-this invention. However, in thecase of the chrome-molybdenum steels a heat treated alloy treated asabove statedpreferably has a Rockwell C scale reading of 50m 55 c In allcases after the alloy is heated to its finaltransformation temperatureit is quenched immediately at this temperature to obtain and retain thedesired fine grain structure plus the desired hardness.

Next this smooth surfaced roll Wasphoto-engraved with a desired patternby means of the conventional lay down Moreover, the disastrous saw toothThe rollers arethen chrome plated to a depthof .0006 1 to .002 or moreinch to produce a chrome plated surface Plating of this thicknessand-quality tends to build up i at the edges of the aembossedcavitiesproducing a hump 16 thereon. This hump of chrome is thicker than on thesurface and it may be polished off to produce a non hurnpslightly'roundedredge 17 of uniform chrome plate depth (FIG. 4). v

The resultant chrome plated roll is therefore one of uniform depth ofcavities, said cavities having round snag- This invention has beendescribed by means of several embodiments .thereoflbut .is not limited10 these illll I ations since itis of a generic scope. V I a I claim:

1. A- snag-proof transfer roll of chrome-molybdenum alloy 'steelengraved for uniform transfer of fluid to a moving monofilament web,said roll. having ,a Rockwell C scale hardness of from .to and having afine I 1.10 percent by weight'and the mol-ybdenumrangeabout.

0.15 to about 0.25,percent -by weight.

' 2.1The transfer roll of claim *1 wherein thecritical transformationtemperature is 1575 and the Rockwell "C scale reading is 53. V

3. The transfer roll of claimd comprising a smooth surface uniformlydeep chromeplating of a depth of .0006 to .002 inch..

References Cited by the 'Examiner UNITED STATES iPATENTS 2,114,072 '4/ 38 Cleveland. 2,725,640 '12/52 Voightman; 2,816,025 12/ 5-7 Dahlberg. V

- 3,048,512 8/ 62 Nelson.

.WALTERA. SCHEELPrimary Examiner.

I. D. .BEIN, Examiner.-

1. A SNAG-PROOF TRANSFER ROLL OF CHROME-MOLYBDENUM ALLOY STEEL ENGRAVED FOR UNIFORM TRANSFER OF FLUID TO A MOVING MONOFLIAMENT WEB, SAID ROLL HAVING A ROCKWELL C SCALE HARDNESS OF FROM 45 TO 60 AND HAVING A FINE GRAINED PRE-ENGRAVED SURFACE STRUCTURE OBTAINED BY HEAT TREATMENT TO FROM TRANSFORMATION POINT TO 25*F. ABOVE THE FINAL TRANSFORMATION TEMPERATURE OF SAID ALLOY FOLLOWED BY QUENCHING AT SAID TEMPERATURE, SAID CHROME MOLYBDENUM ALLOY HAVING A COMPOSITION OF CARBON RANGE 0.45 TO 0.55 PERCENT BY WEIGHT, MANGANESE RANGE 0.60 TO 0.90 PERCENT BY WEIGHT, MAXIMUM AMOUNT OF PHOSPHOROUS 0.40 PERCENT BY WEIGHT, MAXIMUM AMOUNT OF SULFUR 0.050 PERCENT BY WEIGHT, CHROMIUM RANGE ABOUT 0.80 TO ABOUT 1.10 PERCENT BY WEIGHT AND THE MOLYBDENUM RANGE ABOUT 0.15 TO ABOUT 0.25 PERCENT BY WEIGHT. 